Measurements of gravity can be made from aircraft, and are routinely used in some resource exploration, particularly petroleum exploration. A measurement of gravity gradient is preferred for detection of gravity disturbances from an airborne platform, because the direct measurement of gravity cannot distinguish the gravity signal from accelerations associated with the motion of the aircraft. This effect is more pronounced at low altitude surveying, preferred in mineral exploration to improve spatial resolution of the survey, because of the prevalence of atmospheric turbulence close to the ground surface. An ideal gravity gradient measurement will not be sensitive to the motion of the measurement instrument.
A principal source of measurement noise (error) is residual sensitivity of the GGI to motion. The magnitude of the gravity gradient signal expected from an economic mineral deposit is in the range of 1–100 Eotvos (1 Eotvos=10−9 (m/s2)/m). Accelerations experienced in a survey aircraft during low level surveys are generally of the order of 1 m/s2 and the GGI has a baseline length of 10 cm. The acceleration rejection of the GGI therefore must be of the order of one part in 109. The GGI incorporates some mechanisms to achieve high rejection of acceleration but further improvements are required to enable those mechanisms to operate more effectively.